ios遵守mvc设计模式，下面介绍创建控制器viewcontroller的几种方法，来实现页面的跳转

1.纯代码创建

//
//  AppDelegate.m
//  study2024
//
//  Created by zhifei  zhu on 2024/8/7.
//

#import "AppDelegate.h"
#import "MyViewController.h"
@interface AppDelegate ()

@end

@implementation AppDelegate


- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    // Override point for customization after application launch.
    
    //使用自定义viewcontroller,先删除main.storyboard和viewcontroller
    //1.创建窗口并指定大小
    self.window=[[UIWindow alloc]initWithFrame:[UIScreen mainScreen].bounds];
    //2.创建控制器
    MyViewController *myViewController=[[MyViewController alloc]init];
    myViewController.view.backgroundColor=[UIColor greenColor];

    //3.设置为窗口的根控制器
    self.window.rootViewController=myViewController;

    //4.将窗口作为应用程序的主窗口
    [self.window makeKeyWindow];
    
    
    return YES;
}


#pragma mark - UISceneSession lifecycle


- (UISceneConfiguration *)application:(UIApplication *)application configurationForConnectingSceneSession:(UISceneSession *)connectingSceneSession options:(UISceneConnectionOptions *)options {
    // Called when a new scene session is being created.
    // Use this method to select a configuration to create the new scene with.
    return [[UISceneConfiguration alloc] initWithName:@"Default Configuration" sessionRole:connectingSceneSession.role];
}


- (void)application:(UIApplication *)application didDiscardSceneSessions:(NSSet<UISceneSession *> *)sceneSessions {
    // Called when the user discards a scene session.
    // If any sessions were discarded while the application was not running, this will be called shortly after application:didFinishLaunchingWithOptions.
    // Use this method to release any resources that were specific to the discarded scenes, as they will not return.
}


@end

2. 通过storyboard创建控制器

1）、Is initial view controller打上勾

   //通过storyboard创建控制器

    UIStoryboard *uiStoryboard=[UIStoryboard storyboardWithName:@"MyStoryboard" bundle:nil];

    //storyboard只有一个viewcontroller的情况

//    MyViewController *myVc=[uiStoryboard instantiateInitialViewController];

    

    //storyboard有多个viewcontroller的情况，需要使用storyboard id属性

    MyCatViewController *myVc=[uiStoryboard instantiateViewControllerWithIdentifier:@"MyStoryboard1"];

     

    

    [self.view.window setRootViewController:myVc];

2.3、通过xib创建控制器

 //创建控制器的时候同时创建xib页面

    PhotoViewController * myVc = [[PhotoViewController alloc]init];

    [self.view.window setRootViewController:myVc];